Regulation of the combustible mixture in internal-combustion engines



A. M. U'RRANT EGULATUN OF THE COMBUSTIBLE MXTUR NTERNAL CO'vBUSTlONENGINES Filed Jam Villr Patented Aug. 26, 1924.

UNITED STATES PATENT OFFICE.

ALBERT ARTHUR MOLTENO DURRANT, F LONDON, ENGLAND, ASSIGNOR TO THE LONDONGENERAL OMNIBUS COMPANY LIMITED, OF LONDON, ENGLAND, A.

BRITISH COMPANY.

REGULATION OF THE COMBUSTIBLE MIXTURE IN INTERNAL-COMBUSTION ENGINES.

Application led January 2, 1923. Serial No. 610,394.

To all whom t may concern:

Be it known that I, ALBERT ARTHUR MoLTnNo DURRANT, a subject of the Kingof England, residing at Dulwich, London,

England, have invented certain new and useful Improvements in theRegulation of the Combustible Mixture in Internal-Combustion Engines, ofwhich the following is a specification.

This invention is for improvements in or relating to apparatus forregulating the combustible mixture in internal-combustion engines. Thetype of apparatus to which the invention relates is' that wherein -aconduit for the supply of an anti-detonating agent t0 the enginecylinderis controlled by a valve which is operated by a movable member, such asa piston, the movement. of which is controlled by the suction actionproduced by the partial vacuum in the main fuel and air passage of theengine.

It is well known that in some types of internal-combustion engines,particularly with certain fuels, faulty or incomplete combustion of thefuel regularly occurs, with resulting loss in power and efficiency,whenever certain conditions of compression or engine speed exist. Thisunsatisfactory combustion has been described in certain theories asbeing due to detonation, and to overcome it, anti-detonating agents havebeen proposed to be introduced into the combustible mixture. For exampleit has been proposed to add inert gases, such as exhaust gases, to thecombustible mixture for this purpose, this being done either by incomplete scavenging or by adding the exhaust gases to the stream ofincoming combustible mixture. When the compression in the enginecylinder is increased beyond a certain figure, which figure will varydepending upon the type of engine, and type of fuel used, and upon othercircumstances, th looses due to unsatisfactory combustion are muchgreater than at lower degrees of compression, but, of course, a highcompression is normally sought after because a higher efficiency istheoretically obtainable thereat than at low compressions.

This invention has for its main object to provide an improvedconstruction of apparatus of the type referred to such that theanti-detonating agent will be supplied to the combustible mixture evenat high degrecs of compression in the engine cylinder.

A. specific obj ect of the invention is to supply a gaseousanti-detonating agent to the air intake of the engine carburetor.

In apparatus of the type referred to proposed heretofore, the movablemember in the form of a piston has been loaded by a spring that tendedto keep the valve seated so that the supply of the anti-detonating agentwas normally cut off. In such an arrangement, if the suction action inthe main passage was so weak, owing to the throttle being fully open,that the load of the spring on the piston could not be overcome by it,the passage for the supply of the antidetonating agent would be closedwhen the` compression in the cylinder was high.

AccordingA to this invention, apparat-us of the type described forregulating the combustible mixture in internal-combustion engines ischaracterized by the fact that the spring or its equivalent acts on themovable member in such a manner that the latter tends to open the valveagainst the action of the said suction effect which controls themovement of the movable member. In this construction, therefore, thesupply of antidetonating agent to the combustible mixture is controlledby means which are only operative when the engine compression exceeds apredetermined amount.. For effecting this automatic control, thecompression in the cylinder may be estimated or measured by the degreeof opening of the main throttle or the degree of partial vacuum in theengine induction pipe on the cylinder side of the main throttle, sincethe engine compression will normally be at its greatest when thethrottle is fully opened and similarly in such a state of affairs therewill be the least amount of partial vacuum in the engine induction pipe.

Where the engine compression is estimated by the degree of partialvacuum in the engine induction pipe on the cylinder side of the mainthrottle, and the suction action is operative directly on one face ofthe movable member aforesaid, according to another feature of thepresent invention the said movable member is in the form of a flexiblediaphragm to which the stem of said valve is attached. As thisdiaphragml and the valve controlled by it is spring loaded the valvewill only be opened when there is but little partial vacuum in theengine induction p1pe.

In the -foregoing there has been described means for regulating thesupply of antidetonating'agent in accordance with varlations in theengine compression. 'As the compression increases, supplies of anti-detnating agent are introduced into the combustible mixture and thus,although the latter is with certain anti-detonating agents renderedyless eiHcie-nt so far as its power factor is concerned, yet this loss ismore than counterbalanced by the increased efficiency obtained owing tothe prevention of deto nation. v

. For a. more complete understanding of the invention there will now bedescribed, by wayvof example'only and with 'reference to theaccompanying drawings, certain constructional Vforms of mechanismaccording to the present invention.V It is to be understood, however,that the invention is not limited to the precise constructional detailsset forth.

vIn these drawings :--y

Figure 1 is an outside View, partly in section, of certainarts of aninternal-combustio'n engine wit one form of mechanism according to thepresent invention applied thereto;

Figure 2 is a cross-section through' apart of the mechanism shown inFigure l;

"Fi as v Figure 3 is a section on the line 3-3 of re 2, and I igure4 isa detail sectional view on a scale larger than that of theprecedingigures showing a portion of the mechanism. Like referencenumerals indicate like parts throughout the drawings.

Referring to the drawing, the engine induction pipe is, indicated at 10,the main throttle at 11 and the carburetor at 12. Clamped betweenfianges 13 and 14 is alug 15 having a erforation 16 lto coincide withthe borel of tlie induction pipe. The lug 15 projects from a valvecasing 17 havin bosses 18 and 19 which arey bored to orm a fslthroughway 20. The boss 18 is intended to be coupled to a supply ofthe anti-detonating a nt .such as cylinder exhaust gases, and t e boss19 is coupled to a conduit 21 leading to the air intake of thecarburetor 12. The casin 17 has an aperture at its to which is clos/ef?by a cap 22, and below thls cap is situated a valve 23 which controlsthe passage 20. The valve 23 is o f conical formation and has circularseatings 24"and 25 in the casing. The passage 20, where it passes thevalve 23, is increased in width (at 26 Figure 3) and is provided withribs 27 which also form seatlngs forlthe valve. When the valve is downupon its seatin' the passage 20 will be closed but it.will seen that theformation and arran ement of the parts is such that only mslight 'ft ofthe the pressure of the spring 36.

guided in a boss 29 'and this stem is secured at its lower end to aflexible diaphragm 30 of leather, corrugated iiexible metal, or othersuitable material. The outer edges of the diaphragm 30 are securedagainst a face 31 in the casing 17 by a clamping ring 32 and below theclamping ring there is screwed into the easing 17 a cap 33 with adetachable plug 34. The plug 34 is recessed at 35 to house a springv36which at'one end bears against.` a. surface of the plug and at the otherend bears against an abutment 37 on the stem 28.A The spring 36 tends toopen the valve 23.

The diaphragm 30 divides the interior of the casing 17 into twoseparated chambers 38 39. The chamber 38 has a vent 138 to providecommunication with the outside and the chamber 39 `is in communicationwith the interior of the engine induction pipe l0 on the cylinder sideof the throttle 11. For this purpose the passage '40 which extendsbetween the perforation 16 and the clamping ring 32'is provided. Theclamping ring 32 also has fitted into it a. plug 41 having a bore 42 ofsmaller diameter than the bore 40. In this way communication isestablished between the interior of the induction pipe 10 and thechamber 39, the smallness of the bore 42 operating to damp thefluctuations in pressure and secure regularity in the movements 'of thediaphragm due to such iiuctuations in pressure. A securing pin v43 isprovided which is passed through the casing 17 into the ring 32 andwhich operates to prevent the latter from slackening and to maintain itin appropriate alignment withthe bore 40.

In operation, it will be appreciated that when the engine compression ishigh, there will not be a very considerable vacuum established in theengine induction pipe, consequently the difference in pressures in thetwo chambers 38A and 39 will be such that the spring 36 will be able toopen the valve 23. When, however, the compression in the cylindenfalls,the vacuum in the induction pipe will become greater \and vthis willoperate to maintain thevalve 23 closed despite The spring 36 may be madeadjustable to vary the amount of vacuum required to close lthe valve.

The anti-detonating agent employed may be exhaust gases from the enginewhich may be cooled if desired before they are returned to the enginecylinder; or steam generated -say in a coil surrounding the exhaust ipemay be employed; or some other inert 11uent may be employed, or insteadof an inert gas a combustible gas mai be employed which has propertiescapab of correcting the detonating pro ensities of the main fuel, forexample alco ol injected through a needle valve may be employed. It willalso be understood that the supply of anti-detonating agent may reachthe cylinder by a path other than that of the engine carburetor.

`l`urther,r the precise constructional details hereinbefore set forthmay be modified in various ways without de arting from the scope of theinvention as dpefined in the claims. For example, instead of employingthe flexible diaphragm 30, the same result will be obtained by employingcollapsible corrugated bellows, say of spun copper to operate thecontrolling valve.

I claim 1. The combination of an induction conduit for fuel and'airleading to the cylinder of an internal-combustion engine, a valvecontrolling said conduit, a carburetor supplying said conduit, a supplyconduit for the supply of a gaseous anti-detonating agent to the airintake of the carburetor, a valve controlling said supply conduit, achamber connected to said induction conduit at the cylinder side of thefirst said valve, a controlling member operatively connected lwith thelatter valve and movable in said chamber under the suction actiontherein 'in a direction to close the latter valve, and

a spring operative on the second said valve tending to open the sameagainst the suction action on said controlling member.

2. The combination of an induction conduit for fuel and air leading tothe cylinder of an internal-combustion engine, a valve controlling saidconduit, a carburetor supplying said conduit, a supply conduit for thesupply of a gaseous anti-detonatin'g agent to the air intake of thecarburetor, a valve controlling said supply conduit, a suction chamberwhereof one wall is constituted by a flexible diaphragm so connected tothe latter valve that suction in the chamber tends to flex the diaphragmso as to close the latter valve, a duct connecting said chamber to saidinduction conduit on the cylinder side of the first said valve, and aspring operative on the second said valve tending to open the sameagainst the action of suction in said chamber.

. 3. The combination with a valve arranged to control a conduit for thersupply of a gaseous anti-detonating agent to the air intake of thecarburetor of an internal-combustion engine, of a suction chamber, acontrolling member movablein said chamber and operatively connected tothe valve and arranged to seat the valve under the .action of suction inthe chamber, and a spring tending to open the valve, said chamber havinga duct for connection to the induction pipe of an internal-combustionengine.

4. The combination with a valve arran ed to control a conduit for thesupply o a gaseous anti-detonating agent to the air intake of thecarburetor of an internal-combustion engine, of a suction chamberwhereof one wall is in the form of a flexible diaphragm that is carriedby the stem of the valve is arranged to seat the valve under the actionof suction in the chamber, and a spring tending to open the valve, saidchamber having a duct for connection to the` induction pipe of theinternal-combustion engine.

5. The combination with a valve arran ed to control a conduit for thesupply of engine exhaust gases to the air intake of the carburetor of aninternal-combustion engine, of a suction chamber whereof one wall is inthe form of a eXible diaphragm that is carried by the stem of the valveand is arranged toy seat the valve under .the action of suction in thechamber, and a spring in said chamber tending to open the valve, saidchamber having a duct for connection to the induction pipe of theengine, which duct has a restricted end that opens into the saidchamber, for the purpose described.

In testimony whereof I aliix my signature.

ALBERT ARTHUR MOLTENO DURRANT.

